Peeves once hid inside a suit of armour over Christmas break during the Triwizard Tournament. As the armours were singing Christmas Carols, Peeves began to fill the gaps between lyrics with crude phrases and words. Argus Filch had to extract Peeves from the suits on occasion.

Behind the scenes

The suits of armour seem to have a degree of sentience, as a suit's head turned to follow Harry when he was going to Umbridge's Office, and another suit laughed as Neville tripped on the stairs.

While the suits of armour are harmless in the books/films, in some of the video games the Knights also serve as obstacles. In some versions, they attempt to attack Harry with their swords. In the PS2 version of Harry Potter and the Prisoner of Azkaban, the player must sneak past them and avoid their line of vision, else they will stomp and creak loudly when seen.

The knights that appear in Harry Potter and the Deathly Hallows: Part 2 are not, indeed, suits of armour; they appear to be either stone or terracotta statues and do not come in shapes and sizes like gargoyles and different animals in the books. However, they have different helmets and it is possible that some of them are suits because in the book, statues also protected the castle.

In Deathly Hallows: Part 2, the shields of the suits of armour in the front row have the House crests and Hogwarts crests on them: The far left a Gryffindor crest, the second from the left a Hufflepuff crest, the middle knight the Hogwarts crest, the second from the right a Ravenclaw crest, and the far right a Slytherin Crest.